Flight: SHD

       Name: SHD                                                     [Show more]
       Type: Subroutine
   Category: Flight
    Summary: Charge a shield and drain some energy from the energy banks
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * ChargeShields calls SHD


 Charge up a shield, and if it needs charging, drain some energy from the
 energy banks.


 Arguments:

   X                    The value of the shield to recharge


 DEX                    ; If we get here then we just incremented the shield
                        ; value back around to zero, so decrement it back down
                        ; to 255 so it stays at the maximum value of 255

 RTS                    ; Return from the subroutine

.SHD

 INX                    ; Increment the shield value

 BEQ SHD-2              ; If the shield value is 0 then this means it was 255
                        ; before, which is the maximum value, so jump to SHD-2
                        ; to bring it back down to 255 and return without
                        ; draining our energy banks

                        ; Otherwise fall through into DENGY to drain our energy
                        ; to pay for all this shield charging